[Identification and determination of biologically active substance in sterinol]

Due to a wide application of sterinol as a disinfecting agent in medicine and the alimentary industry, and to a resulting possibility of finding it in the waste waters as a composition effectively retarding the process of their biological purification, we undertook an effort to identify and quantify benzyldimethyllaurylammonium bromide. Quantification of BrBdLA was carried out by means of the argonometric determination of the bromium anion, employing the conductometric, potentiometric, and volumetric (i.e. the Mohr) method. BrBdLA was also determined by means of titration in two phases, with ues of sodium dodecyl sulphate against the rose bengal indicator. The ability of BrBdLA to dump the maximum of the oxygen wave was utilized for establishing the polarographic method of its determination. The discussed bromide forms an orange-colour associate with Chrome azurol S, giving two absorption maxima in the visible light region, and namely at 530 and 600 nm. We benefited from this property, when simply identifying ST, and when establishing a new spectrophotometrical method of BrBdLA quantification, which is the biologically active component of sterinol. We draw the calibration curve at lambda = 600 nm, its regression parameters being a = 0.021 and b = -0.027, and the correlation coefficient equal to 0.9993. The established method is simple and reliable, an it can be applied for determination of BrBdLA in the concentration range from 1 to 50 mg/dm3, both in the commercial ST samples and in the ST-containing waste waters, which is going to be the subject of our further studies.